Fast H.264 Skip Mode Selection Using an Estimation Framework (original) (raw)
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A MAP Framework for Efficient Skip/Code Mode Decision in H.264
2006 International Conference on Image Processing, 2006
While the H.264 standard offers improved compression efficiency compared with prior video coding standards, this efficiency arises at the cost of significant complexity. We present a reduced complexity coding algorithm which estimates, prior to coding each macroblock, whether the coder would choose the skip or code mode for the macroblock. Computation savings are achieved, since precoding of skipped macroblocks is avoided. The decision to skip a macroblock is based on estimating and modelling mode cost differences, and employing these models in a MAP framework. Results are shown which indicate that for low-activity sequences savings of over 70% in computation time can be achieved with little or no decrease in video quality.
Efficient mode selection for H.264 complexity reduction in a Bayesian framework
Signal Processing-image Communication, 2008
In order to achieve a high compression ratio, the H.264/AVC standard has incorporated a large number of coding modes which must be evaluated during the coding process to determine the optimal rate-distortion tradeoff. The coding gains of H.264/AVC arise at the expense of significant coder complexity which may not be desired for mobile devices with limited battery life. One coder process that has been identified as having potential for achieving computation savings is the selection between skipping the coding of a macroblock and coding of the macroblock in one of the remaining coding modes. In low-motion subsequences, a large percentage of macroblocks are "skipped", that is, no coded data are transmitted for these macroblocks. By estimating which macroblocks are to be skipped during the coding process, significant savings in computation can be realized, since the coder then does not evaluate the ratedistortion costs of all candidate coding modes. In this work we place this skip versus code decision in a Bayesian framework. We use the rate-distortion cost difference between coding and skipping a macroblock as the single decision feature and determine an appropriate decision threshold following modeling of the cost difference's class-conditional PDFs. Finally, in order to further limit system complexity, we model the threshold's parameters as functions of application-and sequence-specific characteristics, namely, the quantization parameter and an activity factor. This results in a decision threshold that is only a function of these two characteristics, which are either known or easily measured. It is shown that this approach can result in a time savings of over 80% for low-motion sequences at a negligible decrease or, in certain cases, a slight increase in quality over a reference H.264 codec. J J J J J d code J J skip J S J S J S J code J S µ ! "!
2009
A fast macroblock (MB) mode decision algorithm is proposed to reduce the computational complexity of H.264 video coding. First, a SKIP mode detection algorithm is developed to detect as many "skipped" MB as possible. As a result, the encoding functions associated with all inter modes and all intra modes can be omitted. In addition, an early inter mode termination mechanism is developed to disable some inter modes and all intra modes during the motion estimation process. Compared with JM FFS, the proposed algorithm can reduce 71.35% of the encoding time with a negligible degradation in video quality and compression ratio.
Sequence Independent very Fast Mode Decision Algorithm on H.264/AVC Baseline Profile
2006
In this paper we propose a new fast mode decision (FMD) algorithm for H.264/AVC to reduce the computational load of the motion estimation (ME) process. It is oriented to dramatically reduce the encoding time regardless of the level of motion present at the sequences (high or lowmotion). The algorithm decides as the best mode the SKIP Mode or Mode 1 without need to compute the rest of coding alternatives if some conditions are satisfied. These conditions ensure these modes to be used appropriately for low motion and high motion sequences respectively to achieve an appropriate rate distortion (RD) cost based on the results of the previous encoded frames. Tests have shown reductions of the encoding time around -81% for all kinds of sequences, while moderate loss of coding efficiency.
Low complexity inter-mode selection for H. 264
Image Processing, 2006 IEEE …, 2006
The coding efficiency of the H.264/AVC standard enables the transmission of high quality video over bandwidth limited networks. Due to the use of multiple Macroblock (MB) partitions, the Motion estimation module has extremely high complexity that makes it unpractical for most real-time applications on resource-limited platforms such as hand held devices. In this paper we propose a novel algorithm that significantly reduces the encoding complexity while maintaining high rate distortion performance. The proposed method reduces the Motion estimation (ME) computational complexity by accurately predicting the optimal MB partitions and restricting the number of candidate modes based on a-priori probabilities computed from spatio-temporal information. The experimental results show that the speed up of UmHexagonS [1] (one of the most efficient ME algorithms) can be doubled while maintaining the coding efficiency of Full Search.
A framework for fast mode decision in the H264 video coding standard
Digital Signal Processing, 2007
We propose a novel framework for fast mode decision in the simple and main profiles of the H264 video coding standard. Our framework consists of a specific combination of algorithms, each achieving computational savings while retaining rate distortion (RD) performance very similar to the standard. In particular, we utilise a set of skip mode conditions for P and B slices, two heuristics that reduce the cardinality of the inter mode set to be examined, inter/intra mode prediction and the monotonicity property of the rate distortion cost functions. We achieve content dependent savings in run times between 5.8 and 90.1% as compared to H264. Compared to other work that was used as input to the standard, our scheme is faster by 9-23% for very similar RD performance. The proposed framework can be used wholly or partially for computational speed-ups, it is independent of the motion search method used and is applicable in both the rate controlled and nonrate controlled cases.
A novel rate-based macroblock classification for fast mode decision in H.264 video coding
2011
In this paper, a novel rate-based macroblock classification is proposed for fast mode decision in H.264 video coding standard. The main idea is to classify each macroblock into simple or complex motion contents based on the Inter16x16 mode's residue block bit-rate and then according to the classification different mode searching orders with distinct early termination schemes are employed. This new algorithm is very simple for both hardware and software implementations without extra computational module. To speed up the intra mode decision, a new fast Intra 4x4 mode selection algorithm is also proposed by choosing most likely modes using the low complexity SATD cost as screening function. It is demonstrated by experimental results that the proposed fast algorithm can reduce 47% to 65% of the H.264 total encoding time with negligible degradation in the rate-distortion performance. While the rate-based algorithm combined with the fast intra mode selection method could further speedup 5% to 10% of the encoding time with only little rate-distortion degradation.
Fast mode-decision for H.264/AVC based on inter-frame correlations
Signal Processing: Image Communication, 2009
The H.264/AVC standard yields higher coding efficiency rates than other video coding standards. This is because it uses the rate-distortion optimization (RDO) technique, which selects the optimal coding mode and a reference frame for each macroblock (MB). In order to achieve this, the encoder has to encode a given block by exhaustively using all kinds of combinations (including different intra and inter-prediction modes). As a result, the computational complexity of video coding in H.264/AVC is extremely high. In this paper, two fast intra-/inter-mode-decision algorithms are proposed to reduce the complexity of the encoder. Both of these algorithms are based on the inter-frame correlation among adjacent pictures. For the fast intra-mode-decision, we used the intra-mode of the mostcorrelated MB at the reference frame to encode the current MB and the stationary property of the current MB was used for the fast inter-mode-decision. The simulation results show that the proposed algorithms significantly reduced the computational complexity with a negligible loss of PSNR and a slight increase in bitrate.
IJERT-Modified Macroblock Mode Decision Method For H.264/AVC
International Journal of Engineering Research and Technology (IJERT), 2013
https://www.ijert.org/modified-macroblock-mode-decision-method-for-h.264avc https://www.ijert.org/research/modified-macroblock-mode-decision-method-for-h.264avc-IJERTV2IS70785.pdf In video transmission compression, data rate, and bandwidth availability are the major constraints. To overcome them new standard is developed after H.262, H.263 named as H.264.The MPEG-4 Part-10,AVC/H.264 standard is developed jointly by ITU-T Video Coding Expert Group(VCEG) and ISO/IEC Moving Picture Expert Group (MPEG) is widely used for video data transmission.H.264 standard achieves much higher compression efficiency compared to contemporary video coding standards. This is at the expense of higher computational complexity at encoder. Our work focuses on reducing the complexity while improving the performance in coding. For optimum mode decision encoder computes RD costs of all possible coding modes which need lots of computation. The proposed method focuses on the increase of skip mode per macroblock as well as per frame to reduce the bit rate.
An Efficient Mode Decision Algorithm for H.264/AVC Encoding Optimization
IEEE Transactions on Multimedia, 2000
The H.264 video coding standard significantly outperforms previous standards in terms of coding efficiency. However, this comes as a cost of extremely high computational complexity due to mode decision where variable block size Motion Estimation (ME) is employed. In this paper, we propose an efficient algorithm to jointly optimize mode decision and ME. A theoretical analysis is performed to study the sufficient condition to detect all-zero blocks in H.264, and thus adaptive thresholds are derived to early terminate mode decision and ME. Besides the aforementioned early termination technique, the proposed algorithm also introduces temporal-spatial checking, thresholds based prediction and monotonic error surface based prediction methods to skip checking unnecessary modes. Experimental results demonstrate that the proposed algorithm can significantly reduce the computational complexity of H.264 encoding while maintaining almost the same Rate Distortion (RD) performance as the original encoder.